Sheet metal internal-combustion heater



May 9, 1950 G. w. ALLEN ET AL SHEET METAL INTERNAL-COMBUSTION HEATER 4 Sheets-Sheet 1 Filed June 14, 1946 Jay/301651411 4/ dam/ 5 Gear/9e Meir/2,0107%. m &/;a MW

May 9, 1950 e. w. ALLEN ETAL SHEET METAL INTERNAL- COMBUSTION HEATER 4 Sheets-Sheet 2 Filed June 14, 1946 May 9, 1950 G. w. ALLEN 1- AL SHEET METAL INTERNAL COMBUSTION HEATER 0 3 fm V W W H Filed June 14, 1946 Geo/r 9" Z/ sv/ywm /l.

May 9, 1950 G. w. ALLEN ET AL SHEET METAL INTERNAL-COMBUSTION HEATER 4 Sheets-Sheet 4 Filed June 14, 1946 Patented May 9, 1950 SHEET METAL INTERNAL-COMBUSTION HEATER George W. Allen and Vernon N. Tramontini, In-

dianapoli s, Ind., assignors to Stewart-Warner Corporation, Chicago, 11]., a corporation of Virginia Application June 14, 1946, Serial No. 676,776

Claims.

The present invention relates to heaters generally and more especially to the sealed type of internal combustion heater designed for use in aircraft, small boats, automobiles, and the like.

The structure shown and described herein is particularly intended for use in automobiles, and one object of the invention is to provide a heater of compact form having its essential parts closely associated in a single assembly adapted to be readily installed, preferably under the engine hood of the vehicle.

Another object of the invention is to provide a structure for the purpose indicated, so designed as to be economical to manufacture with the parts arranged conveniently for making welded joints where gas-tight connections are important.

It is also an object of the invention to provide an internal combustion heater in which the pipe through which air is supplied for combustion passes through the combustion chamber for preheating the air, and in which the air is discharged from said pipe into a partitioned portion of a burner space to insure thorough admixture of the air with the vaporized liquid fuel.

More specifically it is an object of the invention to provide an internal combustion heater composed largely of coaxially disposed cylindrical sleeves, the innermost sleeve forming the combustion chamber, and the annular spaces between the several sleeves serving as passages for ventilating air to be heated and for the products of combustion in alternating arrangement for the purpose of efficient heat exchange.

Other objects and advantages, including specific features of construction designed to facilitate economical manufacture, will appear more fully from the following description taken in connection with the drawings, in which:

Fig. 1 is a slide elevational view of a heater I embodying this invention;

Fig. 2 is a longitudinal vertical sectional view of the same except that a portion of one end of the heater is left in elevation and adjacent portions are shown broken away to illustrate certain details of the structure;

Fig. 3 is an 'end elevation of the heater as viewed from the left-hand end of the structure shown in Fig. 1, but with certain parts broken away;

Fig. 4 is a transverse vertical section taken as indicated at line 4--4 of Fig. 2;

Fig. 5 is a fragmentary detail sectional view taken as indicated at line 5-5 of Fig. 2; and

Fig. 6 is a horizontal sectional view of a portion of the heater taken as indicated at line 66 of Fig. 2.

As seen in Fig. 1, the heater to which this invention relates includes an outer cylindrical casing so upon which there is mounted a blower l2 for furnishing, air for combustion to the heater. Leading from the blower there is shown the air pipe M bent to enter the interior of the heater through an opening in the casing to at which this section of the pipe is connected to the portion inside the heater by means of a coupling sleeve l6 and clamping ring iii. A solenoid actuated fuel control valve assembly is shown at 29 mounted on the upper side of the casing Ill and a thermostatic control device is illustrated at 22 also surmounting the casing Ill. The exhaust pipe 24 for products of combustion is seen extending from the lower portion of the casing. F

Referring now to Fig. 2, the interior structure is seen to compriseapluralityofcoaxiallydisposed cylinders or sleeves. The innermost cylinder 26 forms the combustion chamber ofthe heater, and the burner mounted 'at one end of this cylinder'includes a frusto conical shell 28 having its base or' larger 'end fitted into the end of the cylinder 26 and closed by a flanged end wall 30. A small chamber or pocket 32is secured in a flanged opening in the end wall 30 and supports the electrically energized igniter which includes a tubular casing 34 open at one end, with a heater coil 36 of resistance wire arranged therein in the usual manner. The igniter tube 34 has its axis horizontally disposed in the pocket 32 so that the liquid fuel fed from the valve device 20 through the feed pipe 38 flows or drips downwardly on to the upper side of the hot tube 34 and a considerable portion of the fuel is thus vaporized. The remainder flows around the surface of the igniter tube 34 on to an absorbent mat or wick 40 composed of fine wire in woven or braided form so that the liquid entrapped therein is readily vaporized by heat radiated from the igniter and from the burning fuel in adjacent portions of the burner. Baffles 33, extending from the side walls of the pocket 32, serve to hold the mat to in place, while permitting any excess of unvaporized fuel to flow between them along the bottom of the pocket 32 and into the adjacent part of the burner shell 28.

The blower I2 secures air for combustion through its intake opening 62 and its rotor is driven by an electric motor shown at 44 protruding into the space provided in the outer casing 26 at one end of the heater and outside the burner. The blower is thus very compactly associated with the heater and the blower casing itself is supported by a specially formed base 46, having a flat circular end wall to which the blower casing is attached, and having a mounting flange 38 which fits the external contour of the casing i 6 around an opening therein through which the motor 44 extends into'thecasing. The air is discharged by the blower l2 through the curved pipe 14 which enters the outer casing it] as already described, and extends through the coaxial cylindrical elements. of the heater for discharging air into the frusto-conical shell 28. A portion [4a extends horizontally within the combustion chamber 26 toward the burner and terminates in an elbow I 417, which is shown in Fig. 2 discharging downwardly just below the horizontal plane of the axis of the burner shell 28. The pocket 32, in which the liquid fuel is vaporized, is also located below this axis, and opposite said pocket 32 the conical burner shell 28 is provided with a vertically disposed baffle wall 56 which is of semicircular outline as seen in Fig. 3, with its straight upper edge located substantially at the axis of the shell 28. This upper edge of the baffle 56 is just above the discharge opening of the elbow Mb and said elbow is located against the curved wall of the shell 28 so that air is discharged from the elbow in substantially tangential relation to this curved wall and downwardly adjacent the open side of the pocket 32. This insures that the vaporized fuel will be picked up by the warm air issuing from the elbow Mb and will become thoroughly intermixed therewith as the air sweeps around the interior of the frusto-conical shell 28; and any liquid fuel which may flow from the pocket 32 into the lowest part of the shell 28 will be quickly vaporized by contact with this warm air sweeping over it. The combustible mixture is initially ignited by the hot wire 36 and the flame is propagated through the mixture and discharged from the smaller end of the shell 28 into the combustion chamber formed by the inner sleeve or cylinder 26'. At the opposite end of the cylinder 26 the chamber is closed by an end wall 52.

The next adjacent sleeve or cylinder 54 is spaced from the sleeve 26 to form a passage 55 of annular cross section open from end to end for the flow of ventilating air to be heated. When the heater is installed in an automobile, a fan or blower, not shown, will usually be connected at one end or the other of the casing [6' to insure the flow of this ventilating air through the passage 55 and into the body of the vehicle for warming the drivers compartment, or the passenger space. or both. In the heater structure as shown, a third sleeve or cylinder 56 is spaced around the sleeve 5 and within the cylinder casing It! in spaced relation to the latter so that a second annular passage 51 for ventilating air is provided between the casing l6 and the cylinder 56. The space Ell-between the sleeves 54 and 56' is placed in communication with the combustion chamber to receive the products of combustion flowing therefrom and to distribute these hot gases over the surfaces of the sleeves 54 and 56 in heat exchange relation with the ventilating air flowing through the spaces 55 and 51-. These hot gases are then conducted away through the exhaust pipe shown at;

The connection between the combustion chamber within the cylinder 26 and the space 59 is formed by a longitudinally extending slot 66 in the cylinder 26 which is disposed in registration with a similar longitudinal slot 6! in the sleeve 54. As seen in Fig. 4, the material of the sleeve 54 which forms the margin of the slot 66 is offset inwardly at 62 by an amount equal to the radial width of the space 55, bringing this marginal area 62 into contact with the outer face of the cylinder 26. Thesecontacting surfaces are electrically seam welded, thus forming a gas-tight joint between the two sleeves around the opening formed by the slots 66 and 6!. This opening provides communication between the combustion chamber and the space 58 substantially throughout the length of the heater. Thus, the hot gases of combustion discharged from the burner space in the shell 28 toward the opposite end of the combustion chamber fill the chamber and then. flow through the opening 66, 6| and distribute themselves in both directions circumferentially through the space 59 toward the exhaust pipe 24 which, as shown in Fig. 4, is disposed diametrically opposite the opening formed by the slots 66 and 6|.

As seen in Figs. 3 and 4, the portion of the sleeve or cylinder 54, which extends opposite the exhaust pipe 24, is flattened at 63 to insure free flow of the gases toward the exhaust pipe. 24; and this flattened surface may have one or more bosses 64 formed in its length for contact with the outer surface of the cylinder 26 to insure proper spacing between the cylinders 26 and 54. At the opposite side of the axis, the connection between. the cylinders at 62, as already described, insures their correct spacing.

The sleeve 56 is spaced from the sleeve 54 by the provision ofrrings 66 to serve as end closures for the space 59 formed between these two sleeves. As shown, these rings telescope within the respective end portions of the sleeve 56 as at 65 and are ofiset inwardly to fit snugly around the end portions of the sleeve 54 at 6'! so that both joints may be conveniently made by seam Welding, the rings being first welded to the ends of the sleeve 56 and then fitted over the end portions of the sleeve 54 and welded thereto. This provides a gas-tight connection between the sleeves 54 and 56 at both ends of the space 59. Intermediate its ends the sleeve 56 is formed with an annular flange 68 which fits snugly around the exhaust pipe 24 in a position in which it can be welded to insure a gas-tight connection at this point. This is, of course, important to prevent the admixture of any of the products of combustion with the ventilating air flowing through the space 57.

The outer casing I6 is preferably made in two parts connected by longitudinal lock seams I0 and H, as seen in Fig. 3, to facilitate assembly. Spacers i2 formed of bent strip stock are welded at intervals to the outer surface of the sleeve 56 and project therefrom for engagement with the inner-surface of the casing 16, as seen clearly in Figs. 3 and 4. The air pipe l4 must be led through all four of the concentric sleeves which form the heater in a manner which will prevent leakage of the products of combustion into the ventilating air passages and 5'5. Therefore the sleeve 56 is formed with an annular flange 74 which fits snugly around the outwardly directed end of the pipe section Ma and which is welded thereto to form a gas-tight joint. This flange or collar 14 is positioned directly opposite the slot 60, 6| through which the combustion chamber communicates with the space 59. At this point the edges of the slot are widened slightly to form arcuate notches 76 which embrace opposite sides of the pipe [4a, as seen in Fig. 6, thus definitely positioning this portion of the air pipe. A straight terminal portion of the pipe section Ma extends through the outer casing l and is connected to the portion 14 outside the heater by means of a coupling sleeve It, as shown in Fig. 1.

The heater is operated by any suitable device which manually or automatically energizes the igniter 35 and supplies fuel and air to the heater. After the heater has started operation, the igniter may be de-energized, if desired.

While there is shown and described herein certain structure embodying the invention and illustrative thereof, it is to be understood that the invention is not limited thereto or thereby, but embraces all modifications, variations and equivalents thereof which come within the scope of the appended claims.

We claim:

1. In an internal combustion heater, the combination of a plurality of coaxially disposed spaced-apart sleeves including an innermost sleeve forming a combustion chamber, a burner for liquid fuel located at one end of said combustion chamber, the innermost and second sleeves forming a passage for ventilating air to be heated and the second and a third sleeve defining a space for products of combustion, said third sleeve and a fourth sleeve forming an additional passage for air to be heated, the innermost sleeve and the second sleeve having longitudinally extending slots disposed in registration, and the marginal portions of said sleeves around said slots being secured together in a gastight joint to provide communication between the combustion chamber and said space for the products of combustion, and a pipe for supplying combustion air to said burner, said pipe extending through said fourth sleeve and said third sleeve, the latter having a collar flange fitted around the pipe and secured in gastight relation thereto, and said pipe extending through the slot in the second and innermost sleeves to the burner.

2. In an internal combustion heater, the combination of a plurality of coaxially disposed spaced-apart sleeves including an innermost sleeve forming a combustion chamber, a burner for liquid fuel located at one end of said combustion chamber, the innermost and second sleeves forming a passage for ventilating air to be heated and the second and a third sleeve defining a space for products of combustion, said third sleeve and a fourth sleeve forming an additional passage for air to be heated, the innermost sleeve and the second sleeve having longitudinally extending slots disposed in registration, and the marginal portions of said sleeves around said slots being secured together in a gastight joint to provide communication between the combustion chamber and said space for the products of combustion, and a pipe for supplying combustion air to said burner, said pipe extending through said third and fourth sleeves and through the slot in the second and innermost sleeves to the burner, the margins of said slots having arcuate notches embracing said air pipe to retain it at a definite position in said slots.

3. In an internal combustion heater, the combination of a plurality of coaxially disposed spaced.apart sleeves including an innermost 6 sleeve forming a combustion chambena burner for liquid fuel located at one end of said combustion chamber, the innermost and a second sleeve forming a passage for ventilating air to be heated and the second and a third sleeve defining a space for products of combustion, said third sleeve and a fourth sleeve forming an additional passage for air to be heated, registering slots in the innermostand second sleeves marginally sealed to providecommunication between the combustion chamber and said space for the products of combustion, and a pipe for supplying combustion air to said burner, said pipe extending through said third and fourth sleeves and through the slots in the second and innermost sleeves at a point removed in an axial direction from said burner thence extending toward said burner in a plane substantially chordally disposed with respect to said innermost sleeve, and thence terminating in an outlet in said burner in a plane substantially diametrically disposed with respect to said innermost sleeve, and said pipe being secured in gastight relation to said third sleeve.

4. In an internal combustion heater, the combination of a plurality of coaxially disposed spaced-apart sleeves including an innermost sleeve forming a combustion chamber, a burner for liquid fuel located at one end of said combustion chamber, the innermost and a second sleeve forming a passage for ventilating air to be heated and the second and a third sleeve defining a space for products of combustion, said third sleeve and a fourth sleeve forming an additional passage for air to be heated, registering slots in the innermost and second sleeves marginally sealed to provide communication between the combustion chamber and said space for the products of combustion, a pipe for supplying combustion air to said burner, said pipe having a goose-neck portion extending through said third and fourth sleeves and through the slots in the second and innermost sleeves at a point removed in an axial direction from said burner and having a portion extending generally chordally of said innermost sleeve toward said burner and terminating in a portion having an outlet in said burner disposed in a plane substantially diametrically disposed with respect to said innermost sleeve, and a collar fiange on said third sleeve fitted around the pipe and secured thereto in gastight relation.

5. An internal combustion heater of the sealed type comprising in combination a plurality of unitary sleeves of relatively thin sheet metal and of varying diameter coaxially disposed to define annular passageways therebetween and including a first or central sleeve closed at opposite ends to define a combustion space, a burner at one end thereof, said first sleeve and a second sleeve having registering slots at least one of which is marginally formed to provide an offset flange which is welded to the margin of the other slot to hold said sleeves in spaced coaxial relation and to form a passageway for establishing communication between said combustion space and the space between said second and a third sleeve, means forming a closure for the ends of the passsageway between said second and third sleeves, said means also functioning to secure said two sleeves in fixed coaxial spaced relation, a fourth sleeve defining an annular ventilating air passageway with said third sleeve, said fourth sleeve forming an external housing for said heater and being adapted to be connected to a source of ventilating air, a pipe for supplying combustion air 7 8 to said burner extending through-said slots and REFERENCES; CITED the fourthslegyes' and anexhawtplpe The following references are of record in the communicating with the space between sald secme of this patent:

0nd and third sleeves, said. pipe being connected in gastight relation to said third sleeve in a por- 5 UNITED STATES PATENTS tion thereofdiametrically opposite said slots and Number Name Date extending through the fourth sleeve. 556,899 Reader Mar. 24, 1896 1,732,174 Sweatt Oct. 15, 1929 GEORGEW. ALLEN. 1,835,297 Grant Dec. 8, 1931 VERN N TRAMONTINI- 10 2,379,018 McCollum June 26, 1945 

